FIEND.fm - "Hot or Not" for music discovery: 2 hrs of tracks in 2 mins
SubmitHub - SubmitHub makes it easy to contact music bloggers, Spotify playlisters, record labels and more. We give you all sorts of statistics and ways to filter who to send your music to.
Music Suggestions Ninja - Enter an artist's name & find similar, lesser known artists
Spotalike - Spotify playlist with similar songs, according to Last.fm
RYSE UP - Connecting up-and-coming artists with the world's top talent
Spotify.me - Beautiful analytics on your Spotify listening habits 🎧